Bovine TB and badgers: “This approach has not been tried anywhere else…”

The different approaches of the various administrations in the UK and Ireland to attempting to eradicate bovine tuberculosis [TB] in wild animals, specifically badgers, are worth noting. They are all in response to the EU Directive 64/432/EEC which, as the Welsh adminstration’s website notes, “requires Member States to provide plans showing how they will eradicate bovine TB in cattle.”

…she had tasked her officials to develop an approach that would involve testing live badgers; vaccinating and releasing the test negative badgers; and removing the test positive ones.

She said: “This approach will focus on removing diseased badgers and protecting uninfected ones. This balanced approach would avoid killing healthy badgers and could lead in time to a healthier badger population incapable of transmitting TB to cattle. This is a powerful message which I hope will be welcomed by environmentalists as well as by farmers.”

The Minister advised that the aim of this wildlife intervention research would be to test the effectiveness of this approach on the level of TB in badgers and in cattle in the north. This approach has not been tried anywhere else and may offer an advantage in moving forward as part of a comprehensive approach that addresses all the factors involved in TB spread.

It’s true that it’s an approach that has not been tried anywhere else. But it was one of the options considered by the Welsh administration. And rejected. Here’s why.

158. There is no field trial evidence to suggest that the combined test, vaccinate and cull approach would reduce the number of confirmed herd breakdowns.

159. The modelling of potential outcomes from the combined test vaccinate and cull approach indicated that the size of the remaining badger population, the level of infection remaining in that population and their disturbance (perturbation) could result in an increase in the number of infected badgers and the number of confirmed herd breakdowns.

160. “There is some support though no evidence base for the value of the removal of individual badgers or setts that are infected and by implication may be epidemiologically important. There is currently no trap-side test that allows for the rapid identification of infected badgers, and there is no information on the outcomes of such an approach with respect to perturbation of badger social structures” (Science Review Report, Page 7, Para 13, see Annex 4). [added emphasis]

161. In conclusion, there is no evidence to suggest that this is a suitable or viable approach to deal with a reservoir of infection in badgers in endemic areas such as the IAA [Intensive Action Area]. [added emphasis]

[Ulster Unionist MLA Robin Swann] “Their intention to trap badgers, vaccinating those which are healthy and culling those which infected, does make sense however I was disappointed that the minister was only able to come to Committee with the headline announcement but very little detail to accompany it.” [added emphasis]

He said significant questions remain however, not least on the practicalities of the testing.

“The department’s intention to use an animal side test with real time results is to be especially welcomed, however they have yet to identify what test they will use and how it will be administered. What we don’t want to see is DARD veterinary officers having to spend exorbitant amounts of time waiting for results of a badger which has to remain anesthetised in a cage beside them.

“Senior DARD officials indicated that they may use a Stat-Pack test, however this was only a possibility, and even then I would be concerned that badgers previously caught and vaccinated may potentially appear positive if caught again.” [added emphasis]

154. There are a number of tests for bovine TB in live badgers. Bacteriological culture of samples, gamma interferon and ELISA tests, can take up to three days for results to be available making them unsuitable for use in this context as badgers would either have to be held captive until the results were available or tested, marked and released then recaptured in the future. The Stat-Pak test is the most promising test for use in a combined vaccination and selective cull strategy. The test is relatively simple to perform, although blood sampling would require badgers to be anaesthetised. The test produces results within 20 – 30 minutes, and has a sensitivity (the ability to identify infected badgers) for detection of bovine TB of 49.2% meaning that half of the truly infected badgers would test negative (and therefore be assumed to be uninfected, vaccinated and released). As discussed later the accuracy of the test is insufficient for the purposes of this option.

And as the Irish Government policy document on badgers, available here, notes [20 December 2011]

Despite considerable research in both Ireland and the U.K. no test on live badgers has proven efficacious in reliably detecting TB infected badgers and thus culling remains the only method of control currently available. [added emphasis]

16. The Science Review recognised that “while a bovine TB Eradication Programme should be informed by the science evidence base, the precise measures adopted will be a political judgement based on an evaluation of a range of factors including the interests of the different stakeholders” (Science Review Report, Page 4, Para 17, see Annex 4). [added emphasis]

One of the first questions for the NI Agriculture Minister to answer is, what resources will be dedicated to developing a “trap-side test that allows for the rapid identification of infected badgers”?

Peter,
No harm and no offence but, are there no farmers around?
I only nosed in out of curiosity but am well aware of the damage TB did in years past

Mister_Joe

I’m not sure what the culling would involve and I don’t know the extent of the TB problem in cattle but it would be a pity if it means killing healthy creatures. Especially if they were there first. Us humans have been a disaster for other animals.

NOT NOW JOHN

“The test produces results within 20 – 30 minutes, and has a sensitivity (the ability to identify infected badgers) for detection of bovine TB of 49.2% meaning that half of the truly infected badgers would test negative (and therefore be assumed to be uninfected, vaccinated and released).”

It seems like tossing a coin might actually be more accurate ….. and efficient.

Reader

NOT NOW JOHN: It seems like tossing a coin might actually be more accurate ….. and efficient.
This test has a problem with false negatives, but tossing a coin instead adds an extra problem – false positives.

http://www.thedissenter.co.uk thedissenter

Minister O’Neill said (today): “I am determined that we will achieve our target of eradicating brucellosis by 31 March 2014. But for this to happen, it is absolutely vital that all herdkeepers take every step to ensure that a very high standard of biosecurity is observed on their farms.”

“The statutory biosecurity guidance brings together in one short document the statutory requirements for herdkeepers specifically in relation to brucellosis, and the recommended key actions that they should take to protect their herd from the risk of the disease. It sets out the existing legal requirements that herdkeepers must meet in respect of brucellosis, as well as the key actions that herdkeepers should take to ensure good biosecurity.”

Reader, I have to confess that I hadn’t fully thought this rather innovative policy out.However on further reflection I’m not sure that there really is a problem. Having a false positive will ensure that more badgers are culled than would be otherwise thus ensuring that those who want badger culls are kept happy ….. while the false negatives will ensure that less badgers are culled than would be otherwise thus ensuring that those who don’t want badgers culled are kept happy. Which is really what the policy is all about. Isn’t it?

Reader

NOT NOW JOHN: Which is really what the policy is all about. Isn’t it?
While I think you are essentially correct, that’s a departure from the usual policy, which is simply to let the farmers have exactly what they want right up to the point at which they start to interact with the food industry.
So what I expected to see was wholesale slaughter.

lamhdearg2

Do we not cull enough on the roads.

Pete Baker

Guys

There’s nothing inherently wrong with the proposed policy.

Indeed, the Welsh government report noted that there was some support for just such an approach.

And since, at this point, the Minister is only proposing research into this particular “wildlife intervention” approach that research could, theoretically, address the current absence of an evidence base “for the value of the removal of individual badgers or setts that are infected and by implication may be epidemiologically important”.

Although the potential “outcomes of such an approach with respect to perturbation of badger social structures” would, I think, give cause for concern.

But the key point is identified in the final quote in the original post.

Timing of the start of any field work is dependent on the successful completion of the necessary preparatory actions…

Unless there is a reliable “trap-side test that allows for the rapid identification of infected badgers” any meaningful research into this approach would be impossible. Using the Stat-Pak test would result in half of the infected badgers trapped being released back into the wild.

And, as the Irish Government policy document notes, “Despite considerable research in both Ireland and the U.K. no test on live badgers has proven efficacious in reliably detecting TB infected badgers”.

So, however sensible the policy may appear at face value, it is currently impracticable.

And the proposed “research” unviable as a way forward.

aquifer

Never mind the handwringing ‘5.4.2 Veterinary Opinion’

There are plenty of badgers and a lot of room to try different approaches including developing this one.

Men tend to look for single silver bullet answers when an effective strategy may be a mixed one including culls when infection is above a certain threshold, but also vaccination for badgers and cattle and even keeping a badger for a couple of days to correlate actual infection rates with the quick test results. Would it be outrageous to sterilise some badgers to keep the overall population down and less likely to wander before 2014?

Pete Baker

aquifer

“There are plenty of badgers and a lot of room to try different approaches including developing this one.”

Starting with developing a reliable “trap-side test that allows for the rapid identification of infected badgers”?

It’s a pre-requisite for the Minister’s proposed approach.

But, “Despite considerable research in both Ireland and the U.K. no test on live badgers has proven efficacious in reliably detecting TB infected badgers”.

Coll Ciotach

Has anyone done any costings? I was wondering if it would not be cheaper just to capture and inoculate and do away with the test phase. The only reason for testing would therefore be to estimate the percentage and spread of disease amongst badgers. Perhaps only testing in areas in and surrounding were the disease is present in cattle? Would inoculation eventually wipe out the disease ?